Many countries increasingly use large numbers of migrant workers, due to the inadequate supply of national labour, the difficulty encountered in filling certain arduous or low paid jobs, or due to the seasonal nature of the work. It is the conditions of work and life of the migrant workers that cause concern. Language difficulties may debar these persons from entering into harmonious human contact and working relationships, leading to social isolation prejudicial to the worker's mental health and safety problems resulting from inability to understand instructions. Provision of satisfactory accommodation is difficult. Families are broken up for the duration of absence or parents and children may keep entirely different working hours, as in the hotel industry. Sometimes the entire nuclear family migrates, in which case links with extended family are weakened. Other times, just the man or woman migrates, leaving behind a family, often with young children -- as in the case with many of the 125,000 Filipina domestic helpers in Hong Kong. Young persons risk mental health problems and delinquency due to the promiscuous manner in which they are thrown together in the absence of parental authority. Workers run medical risks due to diet deficiencies, and they may bring infectious diseases from their country of origin and spread them to the resident population.
Rich countries have always imported labour from poorer ones. In the days of the British Empire, the British imported Tamils and Chinese to work on the plantations and mines of Malaya and Ceylon, Indians to build railways in east Africa and to cut sugar in South Africa. Chinese workers contributed massively to the railroads of the western USA. In the 1960, South Korea began to send coal miners and later nurses to (West) Germany. South Vietnam during the American occupation was another huge labour market for projects out of the firing line. The difference today is not of kind, but of scale and direction. The big Arab oil exporters have grand developmental ambitions but small populations—even Iraq has only 17m people. Singapore, Hong Kong and Taiwan have needed massive labour forces to continue their rapid economic growth.
Pakistani workers abroad sent home more than $16 billion in the ten years to the end of 1986. In 1983 Bengalis working overseas sent back $610m, which is equal to 80% of Bangladesh's merchandise exports and one-quarter of its imports. Filipinos in the same year returned to the Philippines around $950m, which was 3.5% of the GDP. These figures do not include the flourishing black markets and informal arrangements which bypass banking procedures. In 1991, Cuban, Vietnamese and Mozambican guest workers in former East Germany have become the subject of neo-nazi hatred.